Idles high after going from park to gear and back.

[ChevyTech]

Originally Posted by MadRatt

UPDATE: RESOLVED!! Just wanted to give an update as to what we found.
I took the truck to a trans specialist that did some testing and concluded that my converter had no flash stall. So I decided to replace the converter with a HD unit and have them do a inspection of the transmission. He stated that he wasn't sure how the truck actually drove as good as it did based on what he found(he actually test drove it himself). The converter was so loose and actually was able to be spun in the wrong direction without effort(only supposed to spin 1 way). Definitely junk. On inspection of the transmissions clutches he found the second gear packs were completely burned up and the steels were fried. The rest were also over heated just not as bad as the seconds. He thinks maybe something to do with converter just couldn't be sure. So he put all new HD clutch's and steels in it and reinstalled the trans and would ya believe it. It drove home effortlessly. I had to reset all the base Idle stuff in gear and it idles in gear now at 750rpm with 18 counts on the iac and back to park it idles at 850rpm at 13 counts on the iac. I think i'm going to drive it a bit and then reset the base 1 more time and we are good. Couldn't believe that this was the problem but there you have it. $1500 later for all the trans stuff and all the $ for all the other stuff I did. At least I know now that EVERYTHING IS NEW. Should be good for awhile now.

Thank you for your help and everyone else who chimed in with their ideas. It's much appreciated.

Glad to hear it is fixed, and thank you for the update. I wish I could have been more helpful at getting to the cause more quickly. I will remember this thread for a long time.

It is good to see the IAC counts down where they are.